Front Fork. Carbon vs Steel?

[OmahaNeb]

Carbon Fiber fork vs Cromo Fork.  Any suggestions.  If I am going to use front racks, OMM low riders, is carbon going to hold-up?

[wanderingwheel]

My first concern with the carbon fiber fork would be the crush strength in way of the mid-leg mounting point.  Carbon fiber only has it's amazing strength in tension, not in compression, and must be specifically designed to withstand anything above moderate compresion.  Unless you can find a carbon fork with a molded in mounting point, I would be very hesitant to use a carbon fork with a lowrider rack.

Another area of concern is the steerer tube.  To support the added weight of the rack, you shuld use a steel steerer, and a thick one at that.  Maybe a tandem fork would have the necessary steering tube.

I don't see any reason to go with a carbon fork.  It will be more expensive and probably not much lighter than a steel fork.

Sean

[Badger]

I put a carbon fiber fork on my cannondale and won't take it off.  The down turn was that I can't use front end packs.  I got around that by buying a BOB trailer.  I know not everyone is willing to do that but the difference in the ride made it worth the trade off to me.

[biker_james]

There are a couple carbon forks out there now that are designed with maounting points for racks. I'm not sure if they are more weight restricted than steel forks or not though. Met qa fellow this summer with  Marinoni touring bike with a carbon fork and front racks.

[JimF]

Another consideration of steel over carbon fiber: repair in the boondocks. Most any small to moderate fracture in a steel component is relatively easy to repair by anyone with a modicum of welding skill. Not so with a carbon failure.

[OmahaNeb]

Is a carbon fork more vibration dampening than a steel fork?  On my older steel bike, the front fork had a large degree of rake.  On my newer steel bike, there is no rake. I don't see forks these days with the same degree of rake in comparison to older styles.
Also in regard to cracking the carbon fork, with OMM low rider panniers, the lower attachment is via the skewer and the upper attachment just balances the rack without needing much torque on the clamp.  I don't think it would fracture the fork.

[wanderingwheel]

Carbon fiber does transmit less vibration to the rider.  Imagine taking a steel tube and a carbon fiber tube and hitting them both against the ground.  The steel tube would ring and vibrate in your hand but the carbon fiber tube would just thunk like a piece of wood.  However, this does not mean that a carbon fok has any suspension; you will bounce around just as much on a bumpy road regardless if you are on a carbon fork or a steel fork.

All forks have rake, even straight-bladed forks.  In those cases, the rake is done at the fork crown and the fork blades come out at an angle to the steerer tube and place the wheel in same position as if the fork had a visibile rake.  It makes no difference to the handling of the bike if the fork legs are straight or curved and neither one is going to be more comfortable than the other.

I still don't like putting a clamp on the middle of a fork leg that was not designed for it.  Carbon fiber is strong only in one direction, and only in tension.  You will be putting an off-axis compression force on the fork leg and it will be very easy to damage it.

[DaveB]

All forks have rake, even straight-bladed forks.  In those cases, the rake is done at the fork crown and the fork blades come out at an angle to the steerer tube and place the wheel in same position as if the fork had a visibile rake.

Thank you.  You saved me the trouble of typing exactly the same thing.  There is so much mis-understanding as to what rake and trail are and what their relationship is.